899721 has 16 divisors (see below), whose sum is σ = 1363200. Its totient is φ = 586224.

The previous prime is 899719. The next prime is 899749. The reversal of 899721 is 127998.

It is a happy number.

It is not a de Polignac number, because 899721 - 2¹ = 899719 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 899721.

It is not an unprimeable number, because it can be changed into a prime (899711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 915 + ... + 1623.

It is an arithmetic number, because the mean of its divisors is an integer number (85200).

2⁸⁹⁹⁷²¹ is an apocalyptic number.

It is an amenable number.

899721 is a deficient number, since it is larger than the sum of its proper divisors (463479).

899721 is a wasteful number, since it uses less digits than its factorization.

899721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765 (or 759 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 899721 is about 948.5362407415. The cubic root of 899721 is about 96.5389607058.

The spelling of 899721 in words is "eight hundred ninety-nine thousand, seven hundred twenty-one".